Botabt kbixfl



H. R. HUGHES.

ROTARY DRILL CUTTER.

APPHCATION FILED OCT. 28. 1920.

1,412,003. Patented A r. 4, 1922.

A TTQRNEY.

umrao STATES.

mum; o FicE.;

nowsnn a. room, or aousron, rnx as. no'rAnY Damn currit'fsr Specification of Letters we.

- .Patented Apr. 4, 1922.

Application filed October 28, -1 920. Serial No. 420,257.

To all whom it may ooncem: I

Be it known that I, HOWARD a citizenof the United States, residing at Houston,' Harris County, Texas, have invented a certain new and useful Improve ment in Rotary Drill Cutters, of which the 'following is a full, clear, and exact de- 'scri tion, such as will enable others skilled in t e art to which it appertains to make and use the same. 7 y

My. invention relates to an improvement in cutters for use on rollerboring drills and a has especial application to earth boring 9 drills for use in rilling wells for water, oi gas, sulfur, etc.

In drills of this type there is usually a head, approximately cylindrical in shape and scraping action. The chisel action is due to the successive strokes of the teeth. of the cutters upon the bottom of the hole as the cutter rolls rapidly thereon. The scraping action is due to the fact that the cutters are rolling in a circle of a diameter either too small or too large to accommodate the size of the cutter; Asa'result ofthis fact, it has not,1at all points, a true rolling motion upon the bottom of the hole, but tends to slip or scrape upon. the material.

An object of my invention is to so form the teeth upon the cutter as to obtain the greatest possible disintegrating action upon the material being drilled.

Another object is to form a cutter with a plurality of cutting zones thereon, each of which is so formed as to act most efiec tively upon that portion of the bottom of the hole upon which it travels.

will more clearly appear from the detailed These and other. objects and advantages description which follows.

Referring to the drawings, wherein are shownvarious embodiments ofv my nvention, Fig. 1 illustrates, in perspective, a cutter .of cylindrical type having the teeth.

formed thereon according to my invention. Fig. 2 is atop plan view of said cutter.

- Fig. 3 is a plan view of a slightlyv difierent modification of my invention. Figs. 4, 5

andfi show my invention applied to v8.-

i'rious other forms of cutters and g i R. v

whic khan the inner half. Due to the fact I or my invention. Like numerals are applied to like parts throughout the several views.

In forming the teeth upon thecutters to be used with rotary boring drills, I have shown in 'Figs. 1 and 2 a type of. cutter which is commonly'usedwith such: devices. In Fig. 1 the cutter is shown as rotating on about thecenter 0, this point 0 r gfi h he an axis 9 and traveling in a circular prbit the vertical longitudinal axis 0 of the bit upon which the cutter. is mounted. The cutter travels about this central axis 0. in the direction ofthe arrow adj acent thereto in. a clock-wise direction. As the cutter rolls in this circular track about the center said cutter will be in such position as to have a true rolling motion about the central axis of the'bit and forms in this way a neutral plane, between the innerhalf 11 and outer half. 10 of the cutter, neither of'which have of t e cutter will be traveling faster than isnecessary to kee' up with the outer half is traveling in a circle of larger diameter that the two halves are integrally joined and both therefore make the same number of revolutions in'traveling about the center of the bit, there will be a slipping of the inner half 11, thereby allowing the inner half to keep pace with the outer, and likewise on the outer half 10 there will be a slipping, but in an opposite direction. It will be obvious on inspection that the slipping ,on the inner half of the cutter will be in a forward direction, that is in the direction of rotation of the cutter. The teeth-14, formed on the inner half '11, will, therefore, be shaped'to' 55 and 9,1llustrate di'fierent forms of teeth to be used in connection with the application 7 a true rolling motion. As the cutter is cylin- '4 dric lin general outline the irmer half 11.

in Figs. 1 and 7.

The particular form of tooth shown in the drawing has a radial forward face 16 zones 10 and and the rearward face thereof is beveled backwardly and inwardly from the outer edge of the face 16, in such manner as to reinforce and strengthen the tooth as much as possible. For this purpose it has a rearward face 17 inclined only slightly, and a second beveled portion 18, inclined at a still sharper angle, down to. meet the forward face of the tooth next adjacent thereto. While this form of tooth is shown and described in the drawing, it is understood, however, that this particular form is not the only form which this tooth might assume, but that it may be varied as desired with the object of presenting-the sharp edge of the tooth towardthe direction of slippage of the surface upon which the tooth is out.

In the form' illustrated in Figs. 1 and 2, the cutter, in rolling about the central axis of the bit, will strike the bottom of the hole with a sharp chisel stroke as each successive tooth comes in contact with the material. Also there will be a scraping or shearing action of the teeth upon the bottom of the hole, due to the slipping of the cutting surface, because of the fact already explained, that the surfaces do not have a true rolling motion, but tend to slip on the bottom of the:

hole. The inclination of the teeth is such as to give with the slipping action a most efficient scraping or cutting of the material as the cutter rotates.

In Fig. 3 I have shown a'cutter having three cutting zones, an inner zone 11 and an outer zone 10 in the same manner as disclosed in Fig.2, but having in place of the neutral dividing plane 12 an approximately neutral zone 19 between the two cutting 10 and 11 are cut as described in reference to Figs. '1 and 2 to present the sharp edge of the tooth in the direction of slippage upon the bottom of the hole. The central zone 19,

which has only slight slipping action, is formed with teeth 20 which are approximately symmetrical, as shown particularly in Fig. 9. As will be noted the teeth 20 will cut equally well in either direction of rotation of the cutter.

In Fig. 4 I have shown a modification wherein my invention is applied to a cutter frusto-conical in' outline- The smaller circumference of the said cutter is presented toward the central axis of rotation of the bit, but as the outer surface is not so tapered as to bring the apex of the cone, of which the cutter 1s a\ part, at the central axis of rotation of the bit, there is still the same slippresent the sharp cutting,

ner as those 11. The teetlr upon the zones ping action as indicated in the cylindrical. type of'cutter. The outer half 10 ofthe cutter makes the same number of revolutions as the rest of the cutter, and at the same time travels in a larger circumference, and hence is compelled in keeping upwith the rest of the 'cutterto slip upon the bottom of the hole in a clock-wise direction. The inner half of the cutter on the other hand is traveling relatively faster than is necessary to keep u with the rest of the cutter and is compelle to slip upon the bottom of the hole in the opposite direction. The teeth, therefore, on the cutter 4 are formed upon the periphery of the cutter in the same manpreviously described relative to 2.

'Figs. 1 and In Fig. 5 a cutter is shown having the inner half thereof of a smaller diameter than the outer half, both halves being cylindrical in outline, but, as was explained in connection with Fig. 4, the relative size of the inner and outer halves of the cutter is still such that the cutter has not a true rolling motion at any point except upon the neutral plane 12". The teeth are, therefore, formed uponthe outer and inner halves of the cutter as they were described relative to Figs. 1 and 2, the teeth upon. the outer half of the cutter being inclined backwardly from the direction of rotation of the cutter and those upon the inner half being inclined forwardly in the direction of rotation thereof.

Fig. 6 illustrates another embodiment closely like that shown inFig. 2 but differing therefrom only in the fact that the periphery of each half of the cutter is rounded somewhat, as shown in a longitudinal section through the cutter, this rounded periphery serving. to act more efficiently upon differentformations. The purpose of this view is to show merely that this method of forming the teeth upon the cutter is not confined to any particular type or shape of cutter, but may be applied the cutting periphery of with equal success to varied and difi'erent types of cutter.

As will now be readily seen a cutter formed with. teeth out thereon in the manner described will tend to act more rapidly and eflici'ently upon the tegrate the same more rapidly than teeth of the ordinary construction. The inclination of the teeth so that the sharp cutting edge thereof will be presented in the direction that the slippage occurs upon the bottom of the hole will act to perform the usual function of the teeth, that. is to strike the bottom of the hole with a chisel stroke and will, in addition, act to scrape and shear the material thus being drilled and more rapidly, wear and disintegrate the formation. The advantages of this type of cutter will be obvious to one skilled in the art without further explanation, 1

material and to'disin- Having thus described my invention,

. I claim as new and desire to protect by Letters Patent is: v

1. In a roller drill, a cutter adapted to roll on the bottomof the hole with a slipping action of the cutting surface relative to the bottom of the hole, said cutter having teeth thereon cut transversely of the periphery of the cutter, the teeth on one portion being inclined rearwardly and those on the other portion inclined forwardly in the direction of rotation of the cutter so'as to engage .the bottom of the hole most effectively as the teeth slip thereon.

2. In a roller boring drill, a rolling cutter with its periphery shaped to avoid a true rolling action at each end thereof, said cutter having transverse peripheral teeth thereon, the teeth on one end of the peripheral surface being inclined forwardlyand those on the other end being inclined rearwardly relative to the direction of rotation of the cutter to most efiectively engage the bottom of the hole as the teeth slip thereon.

3. In a roller boring drill, a rolling cutter having peripheral teeth thereon, the teeth on the outer end of the peripheralsurface being inclined rearwardly and those on the inner end being inclined forwardly in the direction of rotation of the cutter.

what

4. In a roller boring drill, a cutter adapted to roll on the bottom of the hole with "a slipping action actuated by the rotation of the drill and teeth formed on the peripheral surface of said cutter with a sharp cutting edge which is inclined in the direction of slippage of said surface as the cutter rolls on the bottom of the hole.

5. In a roller boring drill, a cutter adapted to roll in a circular path on the bottom of the hole, teeth on'the periphery of said outter so formed as to provide a neutral plane approximately midway between the ends thereof and having the teeth on the outer side of said neutral plane so cut as to present a sharp scraping edge rearwardly and those on the inner sideforwardly in the direction of rotation of the cutter.

6. In a roller boring drill, a roller cutter constrained toroll upon the bottom of the hole by the rotation of the drill, and teeth on the periphery of said cutter, those on one end being inclined forwardly in the direction of rotation and those on the other end inclined in the opposite direction in the manner and for the purpose described. In testimony whereof, I hereunto aflix my signature, this the 22nd day of October, A. D., 1920.

HOWARD R." HUGHES. 

